1. Field
The present disclosure relates to light sensors in general and, in particular, to a solid-state photodetector with voltage variable spectral response.
2. Background
Light sensors or photodetectors have many applications in a variety of fields from scientific instruments to consumer electronics. Light sensors may be used to measure properties of light at particular wavelengths of interest or over a range of wavelengths. For example, a color analyzer may determine the color properties of incident light. Color analyzers may be used to compare color levels of materials or color reference of displays such as computer monitors or televisions.
Spectrometers measure the properties of light over a range of wavelengths of light. Spectrometers may be used for spectroscopy of a light source to determine spectral properties of the light source. Spectrometers may also be used in spectroscopy (e.g., Raman spectroscopy, infrared spectroscopy, etc.) to determine chemical or physical properties of an illuminated sample.
Many current light sensors use photodiodes that are sensitive to light in a range of frequencies. Particular light components (i.e., colors, frequencies, or ranges of frequencies of light) may be detected through the use of color filters or diffraction gratings. For example, a color analyzer may have three photodiodes with red, green, and blue color filters to isolate components of incident light. To sense light intensity across a range of wavelengths, spectrometers typically use optical prisms or diffraction gratings to separate light into component wavelengths and an array of photodiodes that detect the refracted or diffracted light to measure the spectral components.